Urinary 6-sulphatoxy melatonin levels within the menstrual cycle and in patients with premenstrual syndrome.

The present investigation examined the production of urinary 6-sulphatoxy melatonin (aMT.6S) during the early follicular and late luteal (premenstrual) phases in healthy, normal women and in patients with premenstrual syndrome (PMS). There was no significant difference in levels of aMT.6S on either day 6 or 26 of the menstrual cycle between control subjects and those with PMS. There also was no significant change in urinary aMT.6S levels within the menstrual cycle. These findings do not support an involvement of melatonin in the development of PMS symptomatology and are not supportive of the proposed role of melatonin in regulating ovulation in humans. However, our analysis of 12-hr urine samples may have been insensitive to small, yet possibly biologically significant, changes in the amplitude and period of melatonin excretion during the early hours of the morning.